Automobile suspension system



Jan. 15, 1952 D GIACOSA 2,582,775

AUTOMOBILE SUSPENSION SYSTEM Filed Aug. 3, 1948 4 Sheets-Sheet 1 Jan. 15, 1952 D. @IACOSA AUTOMOBILE SUSPENSION SYSTEM 4 Sheets-Sheet 2 Filed Aug. 5, 1948 Jan. 15, 1 952 D. GIACOSA 2,582,775 AUTOMOBILE SUSPENSION SYSTEM Filed Aug. 3, 1948 4 Sheets-Sheet 3 Jan. 15, 1952 D. GIACOSA AUTOMOBILE SUSPENSION SYSTEM 4 Sheets-Sheet 4 Filed Aug. 3, 1948 Patented Jan. 15, 1952 unmzao PATENT OFFICE 2,582,775 AUZZQMQBILQSUSPENSI N s s'rE Dante- Gi'acosa, Tur b. Italy snnucsflmeu usis, 194s; seam. 42;.151-

Iiina r A z i '9 prove the stability when driving around curves when the center of gravity'ofthe-vehi'cle located towards the front, as isthe case in modemcars in which the rear seat is situated materially forwardly of the rear axle.

In order to attain these objects; I connect; the rear axle with the frame bymeans of longitudinal arms pivoted at one end to the frame and" attached at their other-end to the" axle and also by means of a cross rodshaped in such manner as to form a centralcrank.

The two ends of said cross rod-are-attachedto the frame while its central; cranked portion is fixed to the center of the'axle,

e co s uction is ch. that h d us, f oscillation of the longitudinal arms is much; reater than t adius. o he. c ank ftth ud': T e on s l ation. he, re r; ax e durin driv r sili nt def atio s. f s d cranked red take place which are practically on'small s lat but grea ly in r se. 1901.11 ncr as of the width of said oscillations,

The said cranked rod therefore performs the. function of varying the flexibility of thevsuspen sion making it; all themore rigid; asv the width of the displacements of the rear: axle; increase, w ile sm ll isplaoemenmmsr l 2 51 11 nes l ent deformations of the helical springe The invention, shall now, be; described; with, reference to the. accompany ng. l'a' ng 'i, in; which;

Figures 1 to 3-, refer toa first embodimentof; my invention.

Figure 1 is a rear front'viewofrtheisuspension.

Figure 2 is a planview-thereof and.

Figure 3 is a sideview.

Figures 4 to 8 showa modified embodimentvofa my invention.

Figure 4 is apartialrplan view. of the suspen: sion.

Figure 5 is a section on. line V--V of E'igri.

Figure 6 is a section onrline obFig; 4;

Figure 7 is a section on lineofss'Fig. a,

Figure 8isasectionon line vV IlIfirVliII,.of liig; 4'.

Figure-B lsa plan view of a third: embodiment; ofthe invention.

Referring-to Figuresl to3; I denotes an automobile frame, isthedrive shaft, 3 is the cardan, joint and 4 is the diiferential gearbox, from which extend the two half-axles- 5- carrying the wheels 6, the elements 4 and: 5 forming a rigid unit.

denotes the two longitudinal arms each consisting ,of a leaf spring; articulated at one:-

end to the frame I about-.a-horizontalpivot H and secured at its otherend by means of a clamping-device 54 totheouter end'ofthe'associated half-axle 5.

29 denotes two helical springsinterposew be,v tween the frame I and the end portions of the half axles. 33 denotes two-hydraulic telescopic shock absorbers articulated atone end at 32 to the clamps 54 and at their other end at 34 to a cross member -35-of the framed 45 denotes the" cross rod fixed at its ends at 52 to the frame I and: provided: with a central cranked portion fixed at 5| to' the differential gearbox 4. The said bar may alsobe-arranged in; a symmetricalpositionwithv espect to the reara-xleof the vehicle, as shown in- Fig. 9, so as toconnect to the frame l-'-' ahead ofthe helical springs 29, instead of behind the latter;

The armsfifi are subjectedto a buckling stress on transmission of the propelling forceto; theframe- 1-, and their resilient yielding eliminates; the rigiditydue toconventiona1' arms; said arms: alsoreact resilientlyunder the action ofrbraking and of torsional movements of' the rear axle.

The rod. 45* controlsthe transverse flexibility and: inclination when driving overcurves; More-r over, it serves for automatically varying the char: acteristics of: the suspension making. it harder as the width of the oscillationof; the suspended parts increases. Small oscillations; due to current unevenness of the road, practicallyi-leavesaid rod nafi da d t e suspensionipr se ves szmax mum: flexibil ty; the eact o bein me ely; a en unby the helical'tsp in si Thiss duevtot e fa tthathe; ad um-of the rank; of; the; rod 5 much,;smallcr thanwthe radiusof' oscillation; R1 of? the; arms 60.. Conseq ently, on con d able disp ac me ts of the: rear axle.- t e rod, 1 under oes a; r s l ent d fermationproportioned to: the width of; said displacem t-.- ich s: dded tQ- hed formatm io the. hel cal s n s: 1, e e ye i e h susp ns n.

When" he od 7 s; ar anged; as. denoted: in, Fi s. 1-8 of thgrdrawissiqeimmienswh ms increase, while by the arrangement denoted by 45 in Fig. 9 said deformations increase less sharply.

Referring now to the embodiment shown in fuller details in Figures 4 to 8, 1 denotes the floor of the car supported by the frame I, having attached thereto two angle plates 8, 9 between which a reinforcement C-shaped plate I is interposed.

H denotes a horizontal bolt extending through the suitable holes in plate 8, 9 and. I0 and secured thereto. Spacing washers l2, l3, 14 are fitted on the ends of the bolt II which carries centrally a bushing on which are mounted two rubber bushings I8, I9. 20 denotes a cylindrical element forced on said rubber bushings and bridging the same. The said element is formed with a hollow extension 20a which accommodates the ends of the longitudinal arms 22 which, as distinct from the previously described embodiment, are round tapered rods. Said arms 22 are secured to the cylindrical memberv 20 by welding at 2| and by means of radial pins 23. The opposite end of the arms 22 is clamped between two curved plates 24, ,25 by means of bolts 26 which extend through holes in said plates and are anchored on top to a plate 21 which is clamped by means of said bolts against the end of the associated half-axle 5. 28 denotes a pin preventing rotation of the arm 22 with respect to plates 24, 25.

The plate 21 has secured thereto a plate 28 serving .as'lower rest for the helical spring 29 which bears on top against a plate 30 secured by means of a bolt 3| and with the interposition of a rubber insert 23 to the frame I.

The lower articulation pivot 32 of the shock absorber 33 is supported by a bent portion 24a of the plate 24.

Behind the helical springs 29 a plate 40 is fixed to the frame I underneath floor of the vehicle by means of rivets 39. A further plate 2. In a motor vehicle having a frame, a rigid axle between the two rear wheels and helical springs between said axle and frame, connecting means between said axle and frame comprising longitudinal, round tapered rods articulated at one end to the frame and fixed at their other end to the axle and of a spring steel transverse cranked rod attached at its ends to the frame and at its central portion to the central axle portion, said rod beingcurved in'order to form supplementary spring means progressively reducing the flexibility of the whole suspension 42 is bolted at 4| (Figure 6) to the plate 40.

The two plates 40 and 42 clamp between them a rubber bushing 43 welded thereto and welded at its other end to a flanged metal sleeve 44 accommodating in its interior the ends of the cranked rod 45.

For attaching the central portion of said cranked rod 45 to the differential gearbox 4 I weld to the latter box a plate 49 to which I secure by means of bolts a further plate 48. A rubber bushing 46 is clamped between said plates 48 and 49 and is welded externally thereto and internally to a metal flanged sleeve 46 which receives the rod 45 which is welded to said sleeve The suspension just described operates similarly to the suspension shown in Figures 1 to 3 and need not be further explained.

What I claim is:

1. In a motor vehicle having a frame, a rigid axle between the two rear wheels and helical springs between said axle and frame, connecting means between'said axle and frame consisting of two "longitudinal arms consisting of leaf springs articulated at one end to the frame and fixed at their other end'to the axle and of a spring steel transverse cranked rod attached at its ends to the frame'and at its central portion to the central axle portion, said rod being curved in order to fornis'up'plementary'spring means progressively reducing the flexibility of the whole suspension system for said axle as the width of displacement of the axle'increases.

system for said axle as the width of displacement of the axle increases.

.3. In a motor vehicle having a frame, a rigid axle between the two rear wheels and helical springs between said axle and frame, connecting means between said axle and frame consisting of two longitudinal arms articulated at one end to the frame and fixed at their other end to the axle and of a spring, steel transverse cranked rod attached at its ends to the frame rearwardly of the helical springs and at its central portion to the central portion of the axle, said rod being curved inorder to form supplementary spring means progressively reducing the flexibility of the whole suspension system for said axle as the width of displacement of the axle increases.

4. In a motor vehicle having a frame, a rigid axle between the two rear wheels and helical springs between said axle and frame, connecting means between said axle and frame consisting of two longitudinal arms articulated at one end to the frame and fixed at their other end to the axle and of a spring steel transverse cranked rod attached at its ends to the frame ahead of the helical springs and at its central portion to the central portion of the axle, said rod being curved in order to form supplementary spring means progressively reducing the flexibility of the whole suspension system for said axle as the width of displacement of the axle increases.

5. In a motor vehicle having a frame, a rigid axle between the two rear wheels and helical springs between axle and frame, connecting means between said axle and frame consisting of longitudinal round tapered rods articulated at their tapered end to the frame through rubber bushings and clamped at their other end to the axle and of a spring steel transverse cranked rod attached at its ends to the frame and at its central portion to the central portion of the axle, said cranked rod being curved in order to form supplementary spring means progressively reducing the flexibility of the whole suspension system for said axle as the width of displacement of the axle increases.

6. In a motor vehicle having a frame, a rigid axle between the two rear wheels and helical springs between said axle and frame, connecting means between said axle and frame consisting of two longitudinal arms articulated at one end to the frame and fixed at their other end to the axle and of a spring steel transverse cranked rod attached at its ends to the frame and at its central portion to the central portion of the axle, said rod being curved in order to form supplementary spring means progressively reducing the flexibility of the whole suspension system for said axle as the width of displacement of the axle increases, the attachment of said cranked rod to the frame and central portion of the axle being effected by welding the ends and central portion of said cranked rod to metal bushings encircled .by rubber-bushings clamped between pairs of bolted plates, one plate of the central pair being fixed to the central portion of the axle and one plate of each end pair being fixed to the :frame.

7. In a motor vehicle having a frame, a rigid axle between two rear wheels and helical springs between said axle and frame, connecting means between said axle and said frame consisting of two longitudinal arms articulated at one end to the frame and fixed at their other ends to the axle, and of a spring steel transverse cranked rod attached at its ends to the frame and at its central portion to the central axle portion, said rod being curved in order to form supplementary spring means progressively reducing the flexibility of the whole suspension system for said axle as the width of displacement of the axle increases.

8. In a motor vehicle having a frame, a rigid axle between two rear wheels and helical springs between said axle and frame, connecting means between said axle and said frame consisting of two longitudinal arms articulated at one end to the frame and fixed at their other ends to the axle, and of a spring steel transverse cranked rod 25 attached at its ends to the frame and at its central portion to the central axle portion, said rod Ibeing curved in order to form supplementary spring means progressively reducing the flexibility of the whole suspension system for said axle as the width of displacement of the axle increases, the radius of oscillation of said longitudinal arms being materially greater than the crank radius of the cranked rod.

DAN'IE GIACOSA.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,544,708 Wells July '7, 1925 2,179,016 Leighton Nov. '7, 1939 2,236,410 Leighton Mar. 25, 1941 2,300,844 Olley Nov. 3, 1942 2,345,448 Best Mar. 28, 1944 2,427,927 Shutte Sept. 23, 1947 FOREIGN PATENTS Number Country Date 571,423 France Feb. 1, 1924 

